Artificial denture grinder



Jan. 1, 1935-. H. 'r. JjEDwARDs 4 ARTIFICIAL DENTURE GRINDER Filed July 19, l933- 2 Sheets-Sheet l HurHe. Thomqsjock dwards -1NvENT- Jan. 1, 1935. H. 'r. J. EDWARDS 1,986,523

ARTIFICIAL DENTURE GRINDER Filed July 19, 1933 2 She ets -Sheet2 Thomob zzcK Edwards NVENT K fq.

40 holes by means of which it can be fixed to a i d Claims.

3 whichmay have occurred during constructi'oniin d the upper and lower teethwill be eliminated.

the relationshi'p*-Jrietween-the-worling surfaces of My apparatus comprises abaseupon whichare se'cured two upright's an approximately horizontal arm hinged at itsreare end to=the two=up'-" 1 rights, having at its front endQanadJ'ustabIe-upe right rod and having intermediate its" ends an inverted shallow cup-like depression; and an api proximately horizontal platform slidable upon thetops of small pillars' risiiig from the base and 1 held thereto by a headed studand having intermediate its ends a shallow cup-like depression positioned beneath the inverted cup '-like depres sion on the horizontal arm, such platform' hav ing at its rear end two slotted arms that-engage the bottomends of thetwouprights andhaving out A in aitsaunder surface at" its front end a cir cular' sooket that fits' -neatlyover an eccentric disc upon the top of a vertical shaft carried by the base and operated by a bevel gear drive.

order that niy invencom may-Joe the more clearly understood I will describe the same with reference to .the accompanying drawings in which:

Fig. 1 is a perspective view of my apparatus complete. v a y i Fig. 2 is a central vertical'section of same, and Fig. 3 is a plan view of the movable platform.

In the drawings 1 represents the base upon which are rigidly secured two uprights 2, one.

at each side at the rear. The base has screw tableor elsewhere during operation. An approximately horizontal arm 4 is hinged by its rear end to the tops of the two uprights 2-2, while its forward end is perforated to carry a slidable rod v5. A thumb screw 6 upon the forward end of the arm 4 engages the rod 5 and allows of its adjustment up" or down relative to the forward end of the arm. The lower end of the rod 5 normally rests upon the base 1. Upon the base 1, supported on pillars 8 is platform 9 which is slidable in ahorizontalplane upon the tops of such pillars. It isheld down thereon by a headed stud l screwed into the base and engaging a slot near the rear centre of A Q B UB GBME v. Y Hu rtIe ThomasnJach- Edwariis, Adelaidaj-South Australia, Australia, assig'riorttoiDoxLimit" Adelaida.South-Australia, Australia! "ApplicationlJulya19 1933, serialiNoscenisrn m InrAustralia. August-131; 1932i...

(01. 32:4 d H e-P rm,-thesibt being of s'uificie'nt size 1-;6 permit of the free oscillating m o the platform" It u -b jeccentric disc 15 upon the top of ashaft 16 carried by the b'asefl' upon the top of a verticalshaft 16 supported in the base 1- and is-"operated by a bevelpinion 17 upon its shaft engaging a b'cvel-"whe'el 18 upon a horizon tal shaft 19 also supported in-the bas,the latten sh'aft h'a'ving upon it a; crank handle 20. The centre of the eccentric is .ofiset preferably about? 3/64 of an inch} but may be somewhat-more 'or 1e s 1.1 111 'Iheplatform 9 moves in a horizontal plane, sliding onth'e tops it of -the small pillarsifi which are an integral 'part of the base, andis kept down; accurately} on thesepillars =by' the headed stud' projecting from the basemthrough the elongated oversizehole in the -platform. Both the arm-A 'and the platform 9; have large shallow cup-like depressions intermediate utheir ends, tlfe one 1 n tl'ie iarm facing downward and that 13 on the platform facing upward, and into these depressions the upper and lower artificial dentures respectively are fixed. The dentures are held in place in the depressions by means of plaster of Paris and by removable pins 22 and 23 preferably of stainless steel which pass through the walls of such depressions and hold the plaster therein. 7

The operation of the apparatus is as follows:

The upperand lower artificial dentures are fixed together with wax in the exact relationship which exists when they are in the patients mouth. i d

They are now fixed to the apparatus with plaster of Paris, the upper denture to the horizontal arm 4, and the lower to the platform 9 in such a manner that the median line of the dentures when viewed from the front correspondswiththe median line of the apparatus 1 when also viewed from the front, and the general plane of the chewing surfaces of the dentures (occlusal plane)v is parallel with the plane of movement of the platform.

When setting the dentures in the apparatus the platform is in its rearmost position.

When the'plaster is set the wax is removed from the dentures so that the one can move independently of the other.

The adjustable rod 5 is now loosened, and then fixed with its end about -inch clear of the base 1. This allows the weight of the upper denture which is fixed to the armxi to come on the lowerf denture, and also limits the extent" of the grinding; The grinding ceases when the end of the rod contacts with the base.

Carborundum paste is now spread over the chewing surfaces of the teeth, and'the handle 20 is turned. This imparts a motion to the lower denture similar to that used in natural chew ing with the result that perfect chewing surfaces are quickly worn on the artificial teeth and any errors in their relationship eliminated;

The range of movement is small so that the various cusps and indentations present on the .teeth are not Worn away, but each cusp wears in the opposing teeth a-depression in which it is accurately ground.- In fact the whole of the workingsurfaces become a, series of miniature pestles and mortars with the result that efficiency is markedly increased. 7

What I claim as my invention 'is:-

1. An apparatus for grinding artificial denturescomprising a base, front and rear pillars projecting from said base, an arm hinged to said rear pillars for holding the upper denture, a horizontal platform for holding the lower denture, mounted on said pillars, the mounting for the rear of said platform comprising extensions on said platform having open ended slots therein, fitting about said rear pillars to permit slid-v ing movement of said platform on said pillars, means to hold the horizontal platform down upon the baseand means for slidingly moving said platform on said pillars whereby the front end of the platform follows a circular path.

2. Apparatus as in claim 1 wherein said I hinged arm has means at the front thereof cooperating withsaid base to limit the movement of 'saidfront toward said platform.

3. For grinding artificial dentures an apparatus comprising, abase, a horizontal arm to hold,

the upper denture'hinged at its rear end to the base,,means whereby the'amount of drop of the forward end of the arm toward the base can be regulated; a-horizontalplatform to hold, the lower denture slidable upon the base and having in its rear longitudinal slots capable of backward and forward movement about pins on the base, means for imparting to the forward end of the platform an eccentric 'motion, and means for holding the dentures upon the arm and upon the platform respectively comprising cup-like depressions one above the other that on the arm facing downward and that on the platform facing upward. Y

4. An apparatus for grinding artificial dentures comprising, a base, a horizontal arm hinged at its rear end to the base and having intermediate its ends an inverted shallow cup- "like depression, an adjustable upright rod upon the forward end of' the arm adapted to contact with the base, an approximately horizontal platform slidableupon the tops of small pillars rising from the base and having intermediate its ends a shallow cup-like depression positioned beneath the inverted cup-like depression on the horizontal arm, two slotted arms at the rear end of the platform capable of backward and forward movement about pins on the base, and means for imparting to the forward end of the platform an eccentric motion.

5. In an apparatus for grinding artificial dentures as set forth in claim 4 a headed stud passing into the base through an elongated hole in the slidable platform for holding the platform to the base.

,6. In an apparatus for grinding artificial dentures as set forth in claim 4 means for operating the platform comprising, a disc positionedeccentrically upon a shaft at right angles to the plane of motion of the platform, a bearing in the base for the shaft, and a circular socket in the platform to take the disc.

7. In an apparatus for grinding artificial dentures as set forth in claim 4 means for operating the platform comprising, a disc eccentric upon a shaft at right angles to the plane of motion of the platform, a bearing in the base for the shaft, a circular socket inthe platform to take the disc, a second shaft supported in a bearing in the base and having bevel gears between it'and the first shaft, and a handle upon the second shaft.

HURTLE THOMAS: JACK EDWARDS... 

